Bicycle riding provides pleasure, competition and has the concomitant health benefits of aerobic exercise. The bicycle seat or saddle is a major interface between the rider and the bicycle. It is also the chief support interface between the rider and the bicycle.
To better appreciate this relationship, reference is made to FIG. 1 which schematically shows the bone structure of the human pelvis. The pelvis is a bony structure located at the base of the human spine. The male and female pelvis differ, but the differences are not significant for purposes of understanding the present invention. References a–g identify various dimensions associated with the pelvis. These are common to both male and female. The pelvis is symmetrical in the width direction, with a identifying the pelvic height, b identifying the pelvic breadth, c identifying the anterior upper spinal breadth, d identifying the breath at the pubic symphysis, e identifying the transverse diameter of the pelvic brim, f identifying the height of the ilium, and g identifying the breath of the Sacro-iliac. The bone areas denoted by h are known as the ishial tuberosities or sit bones, and the bone area designated by i are the ischiopubic rami.
Most of the support occurs between the sit bones and the saddle. Depending on the cyclist's posture some support is provided between the horn of a typical saddle and the pubic symphysis/ischiopubic rami (d and i in FIG. 1). The combination of the sit bones and the pubic symphysis/ischiopubic rami provide a bone span which affords a three pronged support interface between the cyclist and the seat.
Since the seat is the chief support interface between the cyclist and the bicycle, the comfort of the cyclist is important to both the pleasure and safety of riding. The size, shape, flexibility, orientation and slickness of the seat will affect the user. Greater comfort of the rider is paramount since greater pleasure and greater duration of riding is a direct consequence of comfort. This translates into better health benefits and less injury.
Almost all known bicycle saddles have a wider aft portion and a forward horn portion. The wider aft portion engages the sit bones and midline soft tissue. The horn provides support to the pubic symphysis/ischiopubic rami and lateral stability by contacting the medial aspects of the rider's thighs.
The typical bicycle saddle has a convex aft portion to provide some degree of pelvis conformation. Pressure from the aft portion of the saddle can cause injury to the tissues around and adjacent the sit bones most notably the pudenal nerve, artery, & vein and cavernous nerve, artery and vein. See, Oberpenning, F., et. al. The Alcock Syndrome: Temporary Penile Insensitivity due to Compression of the Pudenal Nerve within the Alcock Canal, Journal of Urology, 151: 423–425, 1994, and Pavelka, E. Uncomfortably Numb, Bicycling, 39: 89–92, 1998. Some saddles have been designed to reduce pressure to the softer midline structures by providing a fixed slit or space in the middle of the saddle (along the long axis). See, Taylor K. S., et. al. Using an Experimental Bicycle Seat to Reduce Perineal Numbness, The physician and Sportsmedicine, 30: No. 5, May, 2002. Even with a midline space present, there is no accommodating differences in the distance between the ischial tuberosity or interischial tuberosity distance.
See, Niels C. C. M. Moes, Distance Between the Points of Maximum Pressure for Sitting Subjects, International Design Conference—Design 2000, Dubrovnik, May 23–26, 2000. FIGS. 2a and 2b are a reproduction of FIG. 3 of the noted article. The histogram in FIG. 2b shows the variation in the interischial tuberosity distance T. The contour line picture in FIG. 2a show the maximum pressure points. This lack of accommodation for the interischial tuberosity distance can lead to pressure of midline softer structures, which can still lead to lack of blood flow or pressure trauma to the nerves. Additionally, the midline space found in some saddles does not alleviate pressure to softer tissues trapped between the pubic symphysis/ischiopubic rami and horn. Both the lack of accommodating variability in interischial tuberosity distance and pressure from sandwiching tissues between the horn and pubic symphysis/ischiopubic rami can still lead to genital numbness and penile dysfunction.
A seat for a bicycle is needed, therefore, which not only addresses the difficulties noted above but provides a solution to these difficulties.